254 



THE STUDY OF INSECTS. 



mine. When these mines are abundant in a leaf it turns 

 yellow and dies. When the larva has made a mine from 

 one-half to three-fourths of an inch long, which it does in 

 from four to five days, it eats its way out through the upper 

 surface. Then somewhere on the upper 

 surface of the leaf it weaves a circular silken 

 covering about one-twelfth inch in diam- 

 eter. Stretched out on this network the 

 larva, which is now about one-tenth inch long, 

 makes a small hole in it near its edge, then, 

 as one would turn a somersault, it puts its 

 head into this hole and disappears beneath 

 the silken covering, where it undergoes a 

 change of skin. It remains in the molting 

 cocoon usually less than twenty-four hours. 

 After leaving this cocoon it feeds upon the 

 leaves without making a mine; and in a few 

 days makes a second molting cocoon which 

 differs from the first only in being about one- 



Fig. 301. — Cocoons 



of Bucculatrix pom- 

 ifoliella. 



eighth inch in diameter. After leaving this it 



again feeds for a few days, and then mi- 

 grates to a twig where it makes the long 

 ribbed cocoon within which the pupa state is passed. This 

 very interesting life-history was first worked out by Mr. A. E. 

 Brunn while a student in the writer's laboratory at Cornell 

 University. 



When it is necessary to combat this pest the smaller 

 twigs bearing cocoons should be pruned as far as practicable 

 during the winter and burned, and those cocoons that 

 remain on the larger branches should be washed with strong 

 kerosene emulsion. 



The Resplendent Shield-bearer, Aspidisca splendoriferella 

 (As-pi-dis'ca splen-do-rif-e-rel'la). — This Tineid is both a 

 miner and a case-bearer. It feeds within apple-leaves, and at 

 first makes a linear mine ; but later this is enlarged into a 

 blotch mine. When full grown the larva makes an oval case 



